Fix package loading: use shared Julia depot and single project path

Packages were installed to /app as root with depot at /root/.julia,
but the server ran as uid 1000 who couldn't access the root depot.
Now uses JULIA_DEPOT_PATH=/opt/julia-depot (shared) and a single
project path at /home/user/app for both install and runtime.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Dockerfile

@@ -3,25 +3,27 @@ FROM julia:1.10-bookworm
 # HuggingFace Spaces requires user ID 1000
 RUN useradd -m -u 1000 user
 
-# Install Julia packages (cached layer)
-WORKDIR /app
-COPY Project.toml /app/
-RUN julia --project=/app -e 'using Pkg; Pkg.add(["HTTP", "JSON3"]); Pkg.precompile()'
-RUN julia --project=/app -e 'using HTTP, JSON3; println("Precompile done")'
+# Set up shared Julia depot so packages are accessible to all users
+ENV JULIA_DEPOT_PATH=/opt/julia-depot
+RUN mkdir -p /opt/julia-depot && chmod 777 /opt/julia-depot
 
-# Switch to non-root user
-USER user
-ENV HOME=/home/user
-WORKDIR /home/user/app
-
-# Copy application code
+# Copy all application code into /home/user/app
+COPY --chown=user Project.toml /home/user/app/
 COPY --chown=user model.jl /home/user/app/
 COPY --chown=user checkpoint.jl /home/user/app/
 COPY --chown=user server.jl /home/user/app/
-COPY --chown=user Project.toml /home/user/app/
 COPY --chown=user checkpoints/ /home/user/app/checkpoints/
 
-# Default port for HuggingFace Spaces (override with PORT env var)
+# Install and precompile Julia packages
+RUN julia --project=/home/user/app -e 'using Pkg; Pkg.add(["HTTP", "JSON3"]); Pkg.precompile()'
+RUN julia --project=/home/user/app -e 'using HTTP, JSON3; println("Precompile done")'
+
+# Switch to non-root user
+USER user
+ENV HOME=/home/user
+WORKDIR /home/user/app
+
+# Default port for HuggingFace Spaces
 EXPOSE 7860
 
-CMD ["julia", "--project=/app", "/home/user/app/server.jl"]
+CMD ["julia", "--project=/home/user/app", "/home/user/app/server.jl"]